CN100354945C - Optical disk apparatus and method of controlling optical disk apparatus - Google Patents
Optical disk apparatus and method of controlling optical disk apparatus Download PDFInfo
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- CN100354945C CN100354945C CNB2005100926928A CN200510092692A CN100354945C CN 100354945 C CN100354945 C CN 100354945C CN B2005100926928 A CNB2005100926928 A CN B2005100926928A CN 200510092692 A CN200510092692 A CN 200510092692A CN 100354945 C CN100354945 C CN 100354945C
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Abstract
Disclosed herein is an optical disc apparatus for applying a light beam to a surface of an optical disc and detecting a return light beam from the surface of the optical disc. The apparatus includes a light detector for detecting the return light beam having: a light detector having: a first divided area and a second divided area which are divided from each other at the center of the return light beam in a direction perpendicular to a track on the surface of the optical disc; and a third divided area and a fourth divided area which are positioned respectively outwardly of the first divided area and the second divided area in the direction perpendicular to the track. The first and second divided areas are positioned so as not to overlap an area where zeroth-order light and first-order light contained in the return light beam overlap each other.
Description
Technical field
The cross reference of related application
The present invention comprises and Japanese patent application JP2004-238380 that submits to Jap.P. office on August 18th, 2004 and the relevant theme of submitting to Jap.P. office on August 18th, 2004 of Japanese patent application JP2004-238381, and their all contents are incorporated in this as a reference.
The present invention relates to the method for compact disk equipment and control compact disk equipment, and relate more specifically to be used for light beam is applied to optical disc surface and detects the compact disk equipment of Returning beam and the method for controlling this compact disk equipment with photodetector.
Background technology
Up to now, some compact disk equipments comprise the optical pickup equipment according to the operation of so-called three point process, and three point process are used for that track record on the CD forms three luminous points and based on detecting tracking error signal 35 from the Returning beam from the front and back luminous point.Shown in Figure 19 as in the accompanying drawing, optical pickup equipment has the laser diode 2 of emission of lasering beam, and this laser beam converts laser to parallel beam by collimation lens 3.Then convert laser beam to zeroth order and first rank main beam and the auxiliary beam by diffraction grating 4.These main beams and auxiliary beam are reflected by beam splitter 5, and are employed forming three luminous points along slight inclination in the line of the track of dish on 7 by object lens 6, shown in Figure 20 as in the accompanying drawing.Pass object lens 6 and beam splitter 5 from these three luminous points by the Returning beam that dish 7 reflects, and then focused on photodetector 9 according to the light component on the orbital direction of Returning beam by lens 8, this photodetector 9 has three light detection zones corresponding to three luminous points.
As shown in figure 20, the light volume reflection that the front and back light detection zone E of photodetector 9, F detect two auxiliary beams respectively is to generate tracking error signal 35.Especially, two auxiliary beams lay respectively at the opposite side of orbit centre.When the luminous point offset track center of main beam, the light volume reflection of two auxiliary beams changes anti-phasely, as Figure 21 A in the accompanying drawing to shown in the 21D.Detect tracking error signal 35 by the difference (E-F) between the light volume reflection that calculates two auxiliary beams.
Being used for as Figure 19 and shown in from 21A to 21D, three point process that detect tracking error signal 35 required diffraction grating 4 (referring to Figure 19) to be included in the optical system of the optical pickup equipment that is used to form auxiliary beam, and diffraction grating 4 need be adjusted.Therefore, optical system relative complex.In addition, less relatively because be divided into three light beams in the light quantity of the main beam from the light summation of laser diode 2 emitted laser bundles from laser diode 2 emitted laser bundles, the result is lower from the utilization factor of laser diode 2 emitted laser bundles.
In order to address the above problem, known push-pull type process is used to utilize single beam detection tracking error signal 35 (referring to Jap.P. NO.3381873).Figure 22 in the accompanying drawing illustrates the principle of the push-pull type process that is used to detect tracking error signal 35.According to the push-pull type process, incident beam is by pit on the CD or groove diffraction, and the distribution of the light quantity of the diffracted beam in the far-end field is detected by two sections photodetectors 9, and two light detection zone E, F of two sections photodetectors 9 depend on along the light component of the orbital direction of diffracted beam.
According to the push-pull type process, when incident beam and pit or groove alignment, the distribution of the light quantity that is detected by light detection zone E, the F of two sections photodetectors 9 is equal to each other, shown in the Figure 22 in the accompanying drawing and Figure 23 B.When incident beam during not with pit or groove alignment, shown in Figure 23 A or Figure 23 C in the accompanying drawing, the distribution of the light quantity that is detected by light detection zone E, F becomes asymmetric.In fact, when incident beam point from the center of track to the left or to the right during dislocation, shown in Figure 23 A or Figure 23 C, the distribution of the light quantity that is detected by light detection zone E, F becomes asymmetric.Because at incident beam point with opposite direction this asymmetric being reversed during from the orbit centre dislocation, so detected by two sections photodetectors 9 by the difference between the light quantity of light detection zone E, F detection, and in time by average so that make and itself use each pit attribute arbitrarily, produce tracking error signal 35 thus.
Be used for not requiring the diffraction grating 4 (referring to Figure 19) of 3 tracking error signal 35 testing processes according to the optical system of push-pull type process detection tracking error signal 35.Therefore, the circuit arrangement of having simplified this optical system and having made up with it.
Solid line as Figure 24 A in the accompanying drawing is indicated, when the optical axis of object lens 6 with by beam splitter 5 upwards during the center complete matching of laser light reflected bundle, the intensity of laser beam that is detected by photodetector 10 is with respect to its central shaft symmetry.But, shown in dotted line when object lens 6 in the horizontal during dislocation, for example on photodetector 10, be moved to the left at the light beam spot that forms on the photodetector 10, cause the DC skew of the push-pull signal that detects by photodetector 10.
When the Surface Vertical of CD 7 ground is positioned at the optical axis of laser beam, as the solid line indication of Figure 24 B in the accompanying drawing, propagate alignedly by the hole 12 in CD 7 beam reflected and the fixator plate 11, and detected by photodetector 10.At this moment, the light intensity that is detected by light detection zone about photodetector 10 is equal to each other, and does not therefore derive the DC skew in push-pull signal.When indicated as the dotted line of Figure 24 B, disc tilt is displaced to dotted line position among Figure 24 B by CD 7 beam reflected when the optical axis of laser beam, cut off the left-hand component by the folded light beam of hole 12 finishings.When the folded light beam integral body of finishing be moved to not its from here part photodetector 10 about during the light detection zone, the light intensity that is detected by the right light detection zone of photodetector 10 reduces, although the light intensity that is detected by the left light detection zone of photodetector 10 remains unchanged.Especially, because there is not folded light beam to be applied to the part of crescent-shaped of the right light detection zone of photodetector 10, the light intensity that is detected by the right light detection zone of photodetector 10 descends.Therefore in push-pull signal, derive the DC skew, and this laser beam always Be Controlled be offset, also worsened from the signal to noise ratio (S/N ratio) of the signal of video disc recording or reproduction.
In detail, should be with reference to Jap.P. NO.3381873 and the open NO.Hei 11-25482 of Jap.P..
Summary of the invention
A hope of the present invention provides a kind of compact disk equipment, is used for producing tracking error signal and the grating that do not need its optical system, and a kind of method of controlling this compact disk equipment.
Another hope of the present invention provides a kind of compact disk equipment, is used to eliminate the DC component of the tracking error signal that generates when object lens move radially, and a kind of method of controlling this compact disk equipment.
Another hope of the present invention provides a kind of compact disk equipment, is used to remove the DC component of the tracking error signal that generates when CD is tilted optical axis with the dislocation folded light beam, and a kind of method of controlling this compact disk equipment.
Another hope again of the present invention provides a kind of compact disk equipment, is used for removing the skew of when the push-pull type process detects tracking error signal, adding the DC component of error signal to effectively, and a kind of method of controlling this compact disk equipment.
Another hope more of the present invention provides a kind of compact disk equipment, even be used for when the first rank light beam spot that reduces dimensionally is maintained at the central area of photodetector with contacting with each other or overlap each other on the direction perpendicular to the track on the CD, also eliminate the DC component of tracking error signal, and a kind of method of controlling this compact disk equipment.
Of the present inventionly advance a hope and provide a kind of compact disk equipment, be used for producing tracking error signal and focus error signal based on combination from the output signal of two photodetectors, along described two photodetectors of light path arrangement by the Returning beam of CD reflection, and a kind of method of controlling this compact disk equipment.
According to embodiments of the invention, providing a kind of is used for that light beam is applied to optical disc surface and detects compact disk equipment from the Returning beam of optical disc surface, comprise the photodetector that is used to detect Returning beam, this photodetector has on perpendicular to the direction of the track of optical disc surface first marker space and second marker space separate at the center of Returning beam, with the 3rd marker space and the 4th marker space that are placed on first marker space and second marker space outside on perpendicular to the direction of track respectively, first marker space and second marker space are so placed so that the zone that the zeroth order light that is included in the Returning beam and the first rank light are overlapped each other is not overlapping.
According to another embodiment of the invention, providing a kind of is used for that light beam is applied to optical disc surface and detects compact disk equipment from the Returning beam of optical disc surface, comprise first photodetector and second photodetector that are used to detect Returning beam, light path arrangement first photodetector and second photodetector along Returning beam, each of first photodetector and second photodetector has on perpendicular to the direction of the track of optical disc surface first marker space and second marker space separate at the center of Returning beam, with the 3rd marker space and the 4th marker space that are placed on first marker space and second marker space outside on perpendicular to the direction of track respectively, first marker space and second marker space are so placed so that the zone that the zeroth order light that is included in the Returning beam and the first rank light are overlapped each other is not overlapping.
According to still another embodiment of the invention, provide a kind of and be used for that light beam is applied to optical disc surface and detect compact disk equipment, comprise first photodetector and second photodetector that are used to detect Returning beam from the Returning beam of optical disc surface.Light path arrangement first photodetector and second photodetector along Returning beam.First photodetector has on perpendicular to the direction of the track of optical disc surface the 3rd marker space and the 4th marker space that is placed on first marker space and outside, second marker space in separate first marker space, the center of Returning beam and second marker space with on perpendicular to the direction of track respectively.First marker space and second marker space are so placed so that the zone that the zeroth order light that is included in the Returning beam and the first rank light are overlapped each other is not overlapping.Second photodetector has in the 5th marker space at the center that is arranged in Returning beam on the direction perpendicular to track and be placed on the 6th marker space and the 7th marker space of the 5th marker space outside on the direction perpendicular to track.
According to another embodiment again of the present invention, provide a kind of and be used for that light beam is applied to optical disc surface and detect compact disk equipment from the Returning beam of optical disc surface, comprise the photodetector that is used to detect Returning beam.This photodetector has on perpendicular to the direction of the track of optical disc surface the centrosymmetric first and second pairs of marker spaces with respect to Returning beam at least.The first pair of marker space so placed so that the zone that the zeroth order light that is included in the Returning beam and the first rank light are overlapped each other is not overlapping, and is placed in the zone of only using zeroth order light.Second pair of marker space is disposed in the zone of using the first rank light.
First pair of marker space can be placed so that the zone that the zeroth order light and the first rank light are overlapped each other is not overlapping, and can be placed in the zone of only using zeroth order light, orbital direction along from the track of the center of the Returning beam on orbital direction by the zone of dislocation.The first pair of marker space can be arranged on the opposite side at center of the Returning beam on the orbital direction.Replacedly, the first pair of marker space can be arranged on one of the opposite side at center of the Returning beam on the orbital direction.
According to another embodiment more of the present invention, provide a kind of and be used for that light beam is applied to optical disc surface and detect compact disk equipment from the Returning beam of optical disc surface, comprise first photodetector and second photodetector that are used to detect Returning beam.Light path arrangement first photodetector and second photodetector along Returning beam.First photodetector has on perpendicular to the direction of the track of optical disc surface the centrosymmetric first and second pairs of marker spaces with respect to Returning beam at least.The first pair of marker space so placed so that the zone that the zeroth order light that is included in the Returning beam and the first rank light are overlapped each other is not overlapping, and is placed in the zone of only using zeroth order light.Second pair of marker space is disposed in the zone of using the first rank light.Second photodetector has on perpendicular to the direction of track with respect to the centrosymmetric a pair of marker space of Returning beam and the center aimed at first pair of marker space of first photodetector marker space not.
Advance an embodiment according to of the present invention, provide a kind of and be used for that light beam is applied to optical disc surface and detect method from the compact disk equipment of the Returning beam of optical disc surface with photodetector control.This photodetector has on perpendicular to the direction of the track of optical disc surface the 3rd marker space and the 4th marker space that is placed on first marker space and outside, second marker space in separate first and second marker spaces, the center of Returning beam with on perpendicular to the direction of track respectively.First marker space and second marker space are so placed so that the zone that the zeroth order light that is included in the Returning beam and the first rank light are overlapped each other is not overlapping.The method comprising the steps of: use from the output signal of first marker space and eliminate the DC component of tracking error from the difference between the output signal of second marker space; And on compact disk equipment, carry out tracking Control with the signal that the DC component is eliminated.
Can generate tracking error signal by calculating (A-D)-K (B-C), wherein B, C, A, D represent the output signal from first marker space, second marker space, the 3rd marker space and the 4th marker space respectively, and K represents proportionality constant or function.
Advance an embodiment again according to of the present invention, provide the control of a kind of usefulness first photodetector and second photodetector to be used for that light beam is applied to optical disc surface and detect method from the compact disk equipment of the Returning beam of optical disc surface.Light path arrangement first photodetector and second photodetector along Returning beam, each of first photodetector and second photodetector has on perpendicular to the direction of the track of optical disc surface first marker space and second marker space separate at the center of Returning beam, with the 3rd marker space and the 4th marker space that are placed on first marker space and second marker space outside on perpendicular to the direction of track respectively, first marker space and second marker space are so placed so that the zone that the zeroth order light that is included in the Returning beam and the first rank light are overlapped each other is not overlapping.The method comprising the steps of: with first photodetector or second photodetector from the output signal of first marker space and eliminate the DC component of tracking error from the difference between the output signal of second marker space; On compact disk equipment, carry out tracking Control with the signal that the DC component is eliminated; According to combine detection focusing error from the output signal of first photodetector and second photodetector; And the light beam that is applied to optical disc surface is carried out focus control based on focusing error.
Advance an embodiment again according to of the present invention, provide the control of a kind of usefulness first photodetector and second photodetector to be used for that light beam is applied to optical disc surface and detect method from the compact disk equipment of the Returning beam of optical disc surface.Light path arrangement first photodetector and second photodetector along Returning beam.First photodetector has on perpendicular to the direction of the track of optical disc surface the 3rd marker space and the 4th marker space that is placed on first marker space and outside, second marker space in separate first marker space, the center of Returning beam and second marker space with on perpendicular to the direction of track respectively.First marker space and second marker space are so placed so that the zone that the zeroth order light that is included in the Returning beam and the first rank light are overlapped each other is not overlapping.Second photodetector has in the 5th marker space at the center that is arranged in Returning beam on the direction perpendicular to track and be placed on the 6th marker space and the 7th marker space of the 5th marker space outside on the direction perpendicular to track.The method comprising the steps of: with first photodetector from the output signal of first marker space and eliminate the DC component of tracking error from the difference between the output signal of second marker space; On compact disk equipment, carry out tracking Control with the signal that the DC component is eliminated; According to combine detection focusing error from the output signal of first photodetector and second photodetector; And the light beam that is applied to optical disc surface is carried out focus control based on focusing error.
Also advance an embodiment again according to of the present invention, provide a kind of and be used for that light beam is applied to optical disc surface and detect method from the compact disk equipment of the Returning beam of optical disc surface with photodetector control.This photodetector has on perpendicular to the direction of the track of optical disc surface the centrosymmetric first and second pairs of marker spaces with respect to Returning beam at least.The first pair of marker space so placed so that the zone that the zeroth order light that is included in the Returning beam and the first rank light are overlapped each other is not overlapping, and is placed in the zone of only using zeroth order light.Second pair of marker space is disposed in the zone of using the first rank light.The method comprising the steps of: according to the DC component that obtains the tracking error amount from the difference between the output signal of first pair of marker space; With from deducting the output signal that the DC component produces, on compact disk equipment, carry out tracking Control according to the tracking error amount that generates from the difference between the output signal of second pair of marker space.
Can obtain the DC component based on B-C, and generate tracking error signal based on (A-D)-K * (B-C), wherein B, C represent the output signal from first pair of marker space, and A, D represent the output signal from second pair of marker space, and K represents proportionality constant or function.
According to another preferred embodiment, provide the control of a kind of usefulness first photodetector and second photodetector to be used for that light beam is applied to optical disc surface and detect method from the compact disk equipment of the Returning beam of optical disc surface.Light path arrangement first photodetector and second photodetector along Returning beam.First photodetector has on perpendicular to the direction of the track of optical disc surface the centrosymmetric first and second pairs of marker spaces with respect to Returning beam at least.The first pair of marker space so placed so that the zone that the zeroth order light that is included in the Returning beam and the first rank light are overlapped each other is not overlapping, and is placed in the zone of only using zeroth order light.Second pair of marker space is disposed in the zone of using the first rank light.Second photodetector has on perpendicular to the direction of track with respect to the centrosymmetric a pair of marker space of Returning beam and the center aimed at first pair of marker space of first photodetector marker space not.The method comprising the steps of: according to the DC component that obtains the tracking error amount from the difference between the output signal of first pair of marker space of first photodetector; With deducting the output signal that the DC component produces from the tracking error amount that the difference between the output signal of second pair of marker space of first photodetector generates, on compact disk equipment, carry out tracking Control from basis; And based on according to from the output signal of second pair of marker space of first photodetector and and the right output signal in the marker space of second photodetector and between the focus servo margin of error that produces of difference, come the light beam that is applied to optical disc surface is carried out focus control.
Can from from the output signal of second pair of marker space of first photodetector and deduct from the output signal of first pair of marker space of first photodetector and, and can from from the right output signal in the marker space of second photodetector and deduct output signal from the central area of second photodetector.Can ((A+D)-(B+C))-((F+H)-G) generates focus error signal by calculating, wherein B, C represent the output signal from first pair of marker space of first photodetector, A, D represent the output signal from second pair of marker space of first photodetector, F, H represent that G represents the output signal from the central area of second photodetector from the right output signal in the marker space of second photodetector.
According to present embodiment of the present invention, provide a kind of and be used for that light beam is applied to optical disc surface and detect compact disk equipment from the Returning beam of optical disc surface.The photodetector that is used to detect Returning beam has on perpendicular to the direction of the track of optical disc surface the 3rd marker space and the 4th marker space that is placed on first marker space and outside, second marker space in separate first marker space, the center of Returning beam and second marker space with on perpendicular to the direction of track respectively.First marker space and second marker space are so placed so that the zone that the zeroth order light that is included in the Returning beam and the first rank light are overlapped each other is not overlapping.
Above compact disk equipment can used from the output signal of first marker space and eliminate the DC component of tracking error from the difference between the output signal of second marker space on the direction perpendicular to track.
According to another embodiment of the invention, providing a kind of is used for that light beam is applied to optical disc surface and detects compact disk equipment from the Returning beam of optical disc surface.First photodetector and second photodetector that are used to detect Returning beam along the light path arrangement of Returning beam.Each of first photodetector and second photodetector has on perpendicular to the direction of the track of optical disc surface the 3rd marker space and the 4th marker space that is placed on first marker space and outside, second marker space in separate first marker space, the center of Returning beam and second marker space with on perpendicular to the direction of track respectively.First marker space and second marker space are so placed so that the zone that the zeroth order light that is included in the Returning beam and the first rank light are overlapped each other is not overlapping.
Above compact disk equipment can enough first photodetectors or second photodetector from the output signal of first marker space and eliminate the DC component of tracking error from the difference between the output signal of second marker space, on compact disk equipment, carry out tracking Control with the signal that the DC component is eliminated, according to combine detection focusing error, and the light beam that is applied to optical disc surface is carried out focus control based on focusing error from the output signal of first photodetector and second photodetector.
According to additional embodiments again of the present invention, provide a kind of and be used for that light beam is applied to optical disc surface and detect compact disk equipment, be used to detect first photodetector and second photodetector of Returning beam along the light path arrangement of Returning beam from the Returning beam of optical disc surface.First photodetector has on perpendicular to the direction of the track of optical disc surface the 3rd marker space and the 4th marker space that is placed on first marker space and outside, second marker space in separate first marker space, the center of Returning beam and second marker space with on perpendicular to the direction of track respectively.First marker space and second marker space are so placed so that the zone that the zeroth order light that is included in the Returning beam and the first rank light are overlapped each other is not overlapping.Second photodetector has in the 5th marker space at the center that is arranged in Returning beam on the direction perpendicular to track and be placed on the 6th marker space and the 7th marker space of the 5th marker space outside on the direction perpendicular to track.
Above compact disk equipment can enough first photodetectors from the output signal of first marker space and eliminate the DC component of tracking error from the difference between the output signal of second marker space, on compact disk equipment, carry out tracking Control with the signal that the DC component is eliminated, according to combine detection focusing error, and the light beam that is applied to optical disc surface is carried out focus control based on focusing error from the output signal of first photodetector and second photodetector.
According to additional embodiments again more of the present invention, provide a kind of and be used for that light beam is applied to optical disc surface and detect compact disk equipment from the Returning beam of optical disc surface, the photodetector that is used to detect Returning beam has on perpendicular to the direction of the track of optical disc surface the centrosymmetric first and second pairs of marker spaces with respect to Returning beam at least.The first pair of marker space so placed so that the zone that the zeroth order light that is included in the Returning beam and the first rank light are overlapped each other is not overlapping, and is placed in the zone of only using zeroth order light.Second pair of marker space is disposed in the zone of using the first rank light.Use the DC component that obtains the tracking error amount from the difference between the output signal of first pair of marker space, and use from deducting the output signal that the DC component produces according to the tracking error amount that generates from the difference between the output signal of second pair of marker space, on compact disk equipment, carry out tracking Control.
Above compact disk equipment thereby can use the DC component that obtains the tracking error amount from the difference between the output signal of first pair of marker space, and use from deducting the output signal that the DC component produces according to the tracking error amount that generates from the difference between the output signal of second pair of marker space, on compact disk equipment, carry out tracking Control.Therefore, prevent light beam spot always Be Controlled be offset, and prevent from the deterioration of the signal to noise ratio (S/N ratio) of the signal of video disc recording or reproduction.
According to additional embodiments more again of the present invention, provide a kind of and be used for that light beam is applied to optical disc surface and detect compact disk equipment from the Returning beam of optical disc surface.First photodetector and second photodetector that are used to detect Returning beam along the light path arrangement of Returning beam.First photodetector has on perpendicular to the direction of the track of optical disc surface the centrosymmetric first and second pairs of marker spaces with respect to Returning beam at least.The first pair of marker space so placed so that the zone that the zeroth order light that is included in the Returning beam and the first rank light are overlapped each other is not overlapping, and is placed in the zone of only using zeroth order light.Second pair of marker space is disposed in the zone of using the first rank light.Second photodetector has on perpendicular to the direction of track with respect to the centrosymmetric marker space of Returning beam not marker space, center right and that aim at first pair of marker space of first photodetector.According to the DC component that obtains the tracking error amount from the difference between the output signal of first pair of marker space of first photodetector, and use from deducting the output signal that the DC component produces according to the tracking error amount that generates from the difference between the output signal of second pair of marker space of first photodetector, on compact disk equipment, carry out tracking Control.Based on according to from the output signal of second pair of marker space of first photodetector and and the right output signal in the marker space of second photodetector and between the focus servo margin of error that produces of difference, come the light beam that is applied to optical disc surface is carried out focus control.
Above compact disk equipment thereby can be with obtaining from wherein removing the tracking error amount of DC component from the output signal of first pair of marker space of first photodetector with from the output signal of second pair of marker space of first photodetector, on compact disk equipment, carry out tracking Control based on this tracking error amount, according to from the output signal of second pair of marker space of first photodetector and and the right output signal in the marker space of second photodetector and between difference obtain the focus servo margin of error, and the light beam that is applied to optical disc surface is carried out focus control based on this focus servo margin of error.
By following description and in conjunction with the accompanying drawing that illustrates the preferred embodiment of the present invention, the above-mentioned and other target of the present invention, feature and advantage will become obvious.
Description of drawings
Fig. 1 is the block scheme according to compact disk equipment of the present invention;
Fig. 2 is the vertical cross-section diagram of optical system of the optical pick-up of compact disk equipment;
Fig. 3 is the vertical cross-section diagram that shows the layout that is installed in a pair of photodetector on the beam splitter prism;
Fig. 4 A and 4B are the planimetric maps of pattern of the light detection zone of display light detecting device;
Fig. 5 A and 5B are the planimetric maps of other pattern of the light detection zone of display light detecting device;
Fig. 6 is the block scheme that is used for generating according to the output signal of photodetector the treatment circuit of tracking error signal;
Fig. 7 is the block scheme that is used for generating according to the output signal of photodetector the treatment circuit of focus error signal;
Fig. 8 is the block scheme that is used for generating according to the output signal of photodetector another treatment circuit of focus error signal;
Fig. 9 is the view how display beams point and zeroth order and the first rank light beam overlap each other;
Figure 10 A and 10B are presented at the tracking error signal that detects on the photodetector and the chart of light beam spot;
Figure 11 A is the planimetric map that is presented at the light beam spot that detects on the photodetector to 11C;
Figure 12 is the curve map how the detection output signal of display light detecting device changes when the focus state of the light beam spot that detects thus changes;
Figure 13 A is the planimetric map of demonstration according to the pattern of the light detection zone of the photodetector of another embodiment to 13C;
Figure 14 is the block scheme that is used for generating according to the output signal of photodetector the treatment circuit of tracking error signal;
Figure 15 is the block scheme that is used for generating according to the output signal of photodetector another treatment circuit of tracking error signal;
Figure 16 is the block scheme that is used for generating according to the output signal of photodetector the treatment circuit of focus error signal;
Figure 17 is the block scheme that is used for generating according to the output signal of photodetector another treatment circuit of focus error signal;
Figure 18 A and 18B are presented at the tracking error signal that detects on the photodetector and the chart of light beam spot;
Figure 19 is the vertical cross-section diagram of optical system that is used to detect the tracking error of conventional optical disc equipment;
Figure 20 is the chart that shows according to the pattern of the light detection zone of the position of the light beam spot on the CD of three point process and photodetector;
Figure 21 A is the curve map that is presented at the light volume reflection of light beam in three point process to 22D;
Figure 22 is the front elevation of the principle of the explanation push-pull type process that is used to detect tracking error;
Figure 23 A is the planimetric map of the principle of the explanation push-pull type process that is used to detect tracking error to 23C;
Figure 24 A is to show the vertical cross-section diagram that generates the mode that is offset when object lens when laterally dislocation and CD are tilted to 24B.
The specific embodiment mode
Fig. 1 has shown with the overall schematic according to the square frame form of compact disk equipment of the present invention.As shown in Figure 1, compact disk equipment has on the spindle drive motor 21 that is used for rotary CD 20 and the optics optical pick-up 22 towards CD 20.Optical pick-up 22 comprises object lens 23, laser beam sources 24 and photoelectric detector 25.
By the feed motor 28 that is connected with feed servo circuit 29, the optical pick-up 22 that can move radially CD 20.Optical pick-up 22 is also related with focus servo circuit 30 and tracking servo circuit 31.
Compact disk equipment is by following operation: spindle drive motor 21 is around its axle rotary CD 20, and the optical pick-up 22 that is moving radially CD 20 by the feed motor of being controlled by feed servo circuit 29 28.Be applied to the surface of CD 20 from laser beam sources 24 emitted laser bundles by object lens 23, the surface reflection of CD 20 is applied to the laser beam of photoelectric detector 25 by object lens 23.The spindle servo circuit 37 that this photoelectric detector 25 generates RF signal 34 and provides it to control spindle drive motor 21.Photoelectric detector 25 also generates tracking error signal 35 and provides it to tracking servo circuit 31, and tracking servo circuit 31 moves radially the object lens 23 of CD 20, is used for tracking Control.Photoelectric detector 25 also generates focus error signal 36 and provides it to focus servo circuit 30, and focus servo circuit 30 moves object lens 23 along the optical axis of laser beam, is used for focus control.RF signal 34 from photoelectric detector 25 is also handled by the signal processor 38 that produces the output signal of reproducing.
To be described below the details of optical pick-up 22 with reference to figs. 2 to 4A, 4B.Fig. 2 shows and has merged the optical pick-up 22 that is used for detecting according to the push-pull type process optical disk system of tracking error signal 35.From laser diode 24 emitted laser bundles by beam splitter prism 41 reflection and pass a quarter wave plate 42.This laser beam is followed collimated lens 43 and is converted parallel beam to, and this parallel beam is by catoptron 44 reflections and then by hole 46 finishings that define in fixator plate 45.Laser beam then is applied to CD 20 by object lens 23.Returning beam by CD 20 refractions passes object lens 23 and hole 46, and mirror 44 reflections that are reflected are so that pass collimation lens 43 and quarter wave plate 42.Returning beam then passes beam splitter prism 41 and is applied to first photodetector 51 of photoelectric detector 25.Returning beam is reflected by the half-mirror of beam splitter prism 41 surface 48, and by total reflection surface 49 reflections of beam splitter prism 41, thereby drop on second photodetector 52 of photoelectric detector 25.First and second photodetectors 51,52 detect the corresponding light quantity of Returning beam, and produce light signal (RF signal) 34, tracking error signal 35 and focus error signal 36 based on the light quantity of the Returning beam that detects.
First and second photodetectors 51,52 are disposed in the interval that separates on the half-mirror surface 48 of beam splitter prism 41.Shown in Fig. 4 A and 4B, first and second photodetectors 51,52 have respectively four light detection zone A to D and four light detection zone E to H, be used for detecting Returning beam according to light component along the Returning beam of the orbital direction of CD 20.Light detection zone B, the C of first photodetector 51 and light detection zone F, the G of second photodetector 52 be shaped as not be included in Returning beam in the zeroth order light (the directly light of reflection) and the overlapping region of the first rank light (light of diffraction) aim at.
Fig. 5 A and 5B have shown another pattern of the light detection zone of first and second photodetectors 51,52.First photodetector 51 shown in Fig. 5 A has four light detection zone A of the light detection zone that is similar to first photodetector 51 shown in Fig. 4 A to D.But second photodetector 52 shown in Fig. 5 B has three light detection zone E, F, G.This is because tracking error signal 35 is to generate according to the output signal of first photodetector 51, and focus error signal 36 is that combination according to the output signal of first and second photodetectors 51,52 generates.Second photodetector 52 does not need to cut off the DC component so that produce focus error signal 36, and does not require that center light detection zone F is separated into two districts.
Usually, when being applied to CD 20, light beam spot produces Returning beam, the overlapping relation that is included between zeroth order light in this Returning beam (the directly light of reflection) and the first rank light (light of diffraction) changes according to the track record density on the CD 20, as shown in Figure 9.Especially, as long as light beam spot has constant diameter, comprise the zeroth order light and the first rank light that except that orbit centre, in light beam spot, overlaps each other from the Returning beam that has the CD diffraction of big track space such as CD (compact disk) or MD (mini-disk), and the zone of only using zeroth order light does not exist on the direction perpendicular to track.Be included in the zeroth order light and the first rank light that does not overlap each other the central area of light beam spot of Returning beam from have than beam spot diameter Returning beam than the CD diffraction of small track pitch such as DVD (Digital video disc), blue beam dish, HD-DVD etc.Be included in the zeroth order light and the first rank light that does not all overlap each other Anywhere the light beam spot from the Returning beam of CD diffraction with littler track space.Under latter event, can not detect tracking error signal 35 according to push-pull type process based on the first rank light.
According to present embodiment, corresponding to as shown in Figure 9 middle ware distance, and zeroth order light and the first rank light do not overlap each other in the central area of the light beam spot of Returning beam on perpendicular to the direction of track than the track space of light beam spot.Present embodiment is, center light detection zone B, the C that is used to detect the photodetector 51 of Returning beam so placed and be shaped so that the zone that the zeroth order light and the first rank light are overlapped each other is not overlapping.
So be shaped so that the zone that the zeroth order light and the first rank light are overlapped each other is overlapping and be formed like that shown in Fig. 4 A by light detection zone B, C, represent by A-B from the difference between the detection output signal of light detection zone A, the B of photodetector 51, and represent (referring to Figure 10 A) by B-C from the difference between the detection output signal of light detection zone B, the C of photodetector 51.
As mentioned above, because light detection zone B, the C of the photodetector 51 among Fig. 4 A so are shaped so that the zone that the zeroth order light and the first rank light are overlapped each other is not overlapping, therefore so light detection zone B, C are not subject to the influence of the first rank light, and be not subject to generate the influence of the pit and the groove of tracking error signal 35.Therefore, even move object lens 23 with respect to CD 20, perhaps CD 20 is tilted so that the optical axis of dislocation Returning beam, and light detection zone B, C are not subject to reverse influence shown in Figure 10 B by eliminating DC component (skew) B-C yet.Thus, can generate the tracking error signal 35 that does not have the DC skew by calculating from the difference B-C between the detection output signal of light detection zone B, C and calculating (A-D)-K * (B-C) (referring to Figure 10 B).
Fig. 6 has shown the circuit that is used for according to generate tracking error signal 35 from the detection output signal of photodetector 51,52.Circuit shown in Figure 6 has 55,56,57 and multipliers 58 of three subtracters, is used for generating tracking error signal 35 according to above formula (A-D)-K * (B-C).Replacedly, circuit shown in Figure 6 can generate tracking error signal 35 according to formula ((A+B)-(C+D))-K * (B-C).
Can generate focus error signal shown in Figure 1 36 according to combination from the detection output signal of photodetector 51,52.Figure 11 A has shown at object lens 23 when optical axis moves and be displaced to just in time the opposite side of the position that focuses on to 11C, the light beam spot that detects on photodetector 51,52.The light beam spot that detects on photodetector 51,52 is to be focused with respect to the shape of the position that just in time focuses on basic symmetry.
As shown in figure 12, draw out from the difference between the detection output signal of photodetector 51,52.In the position that just in time focuses on, be zero substantially from the difference between the detection output signal of photodetector 51,52.Therefore, can be based on how much detecting from the difference offset from zero between the detection output signal of photodetector 51,52 from the position deviation of the position that just in time focuses on.This has indicated, can be according to from generating focus error signal 36 along the difference between the detection output signal of the photodetector 51,52 of light path arrangement.
Fig. 7 has shown the circuit that is used for according to generate focus error signal 36 from the detection output signal of the photodetector shown in Fig. 4 A and the 4B 51,52.Circuit as shown in Figure 7 has 61,62,63,64 and three subtracters 65,66,67 of four totalizers, is used for generating focus error signal 36 according to formula (A+D)-(B+C)-((E+H)-(F-G)).
Fig. 8 has shown another circuit that is used for according to generate focus error signal 36 from the detection output signal of the photodetector shown in Fig. 5 A and the 5B 51,52.Circuit as shown in Figure 8 has 71,72,73 and three subtracters 74,75,76 of three totalizers, is used for according to formula (A+D)-(B+C)-((E+G)-F) generates focus error signal 36.
The photodetector 51,52 that has the separation light detection zone of the shaping shown in Fig. 4 A and 4B or Fig. 5 A and 5B by use, can detect the tracking error signal that does not have skew, promptly can calculate (A-D)-K * (B-C) so that detect tracking error signal 35, even object lens 23 are moved radially or CD 20 is tilted so that the optical axis of dislocation Returning beam.If center light detection zone B, C, F, G so are shaped so that the zone that the zeroth order light and the first rank light are overlapped each other is not overlapping, can detect tracking error signal 35 by calculating (A-D)+(E-H)-K * ((B-C)+(F-G)) or (E-H)-K * (B-C) so.
The detection output signal of exterior light detection zone A, D that can be by calculating photodetector 51 and (A+D) and the detection output signal of interior lights detection zone B, the C of photodetector 51 and (B+C) between difference and the detection output signal of exterior light detection zone E, the H of photodetector 52 and (E+H) and the detection output signal of interior lights detection zone F, the G of photodetector 52 and (F+G) between difference poor, i.e. (A+D)-(B+C)-((E+H)-(F+G)) comes detection of focus error signal 36.
By the Returning beam of CD 20 refraction pass object lens 23 and mirror 44 reflections that are reflected so that pass collimation lens 43 and quarter wave plate 42.Returning beam then passes beam splitter prism 41 and is applied to first photodetector 51.Returning beam is reflected by half-mirror surface 48, and is then reflected by total reflection surface 49, thereby drops on second photodetector 52.First and second photodetectors 51,52 detect the corresponding light quantity of Returning beam, and produce light signal (the RF signal of the output that expression is reproduced) 34, tracking error signal 35 and focus error signal 36 based on the light quantity of the Returning beam that detects.
If second photodetector 52 comprises three light detection zone E that have shown in Fig. 5 B, three sections photodetectors of F, G, and with the combination of first photodetector 51, so may (A+D)-(B+C)-((E+G)-F) comes detection of focus error signal 36 by calculating.
Another embodiment of various details.If pit train is more coarse or because the reducing of the size of optical pick-up 22 than light beam spot as shown in Figure 9, so light beam spot reduces on diameter than the spacing of pit train, so at zeroth order light on the direction of track and on the first rank light overlaps each other in the central area of light detection zone or influence each other perpendicular to the direction of track.Therefore, on the direction of track and on perpendicular to the direction of track in the central area of light detection zone, the zone (but detected state (bigger modulation)) that does not exist the zeroth order light and the first rank light not to overlap each other with the more coarse pit train among Fig. 9.Therefore in the central area of the photodetector on orbital direction, can not be based on producing the signal that is used to cut off the DC component from the difference between the right detection output signal of the light detection zone of separating, the light detection zone of separation is to so being placed and being shaped so that the zone that the zeroth order light and the first rank light are overlapped each other is not overlapping.
Other embodiment can be applicable to the pit train situation that more coarse or light beam spot reduces on diameter than the spacing of pit train than light beam spot as shown in Figure 9, and on the direction of track and on perpendicular to the direction of track in the central area of light detection zone, the zone that does not exist the zeroth order light and the first rank light not to overlap each other.Other embodiment is, at zeroth order light on the direction of track and on the first rank light overlaps each other in the central area of light detection zone or influence each other perpendicular to the direction of track, and photodetector 81 has light detection zone B1, B2, C1, C2 or B, C as shown in Figure 13 A, 13B or 13C, they are so placed so that the zone that the zeroth order light that is included in the Returning beam and the first rank light are overlapped each other is not overlapping, and are placed in the zone of only using zeroth order light.
Especially, photodetector 81 as shown in FIG. 13A has light detection zone B1, B2, C1, C2, and they so are shaped so that the zone that the zeroth order light that is included in the Returning beam and the first rank light are overlapped each other is not overlapping.By (B1+B2)-(C1+C2) shown in Figure 18 A, wherein B1, B2, C1, C2 indicate the detection output signal from light detection zone B1, B2, C1, C2 corresponding to the signal of the DC offset component of tracking error signal 35.
Because the light detection zone B1 of photodetector 81, B2, C1, C2 so are shaped so that the zone that the zeroth order light shown in Fig. 9 and the first rank light are overlapped each other is not overlapping, therefore so light detection zone B1, B2, C1, C2 are not subject to the influence (the first rank light) of diffraction light, and be not subject to generate the influence of the pit and the groove of tracking error signal 35.Therefore, even move object lens 23 with respect to CD 20, perhaps CD 20 is tilted so that during the optical axis of dislocation Returning beam, and light detection zone B, C (B1+B2)-(C1+C2) are not subject to reverse influence shown in Figure 18 B by eliminating DC component (skew) yet.Thus, can be by calculating from the difference (B1+B2)-(C1+C2) between the detection output signal of light detection zone B1, B2, C1, C2 and calculating the tracking error signal 35 that (A-D)-K * ((B1+B2)-(C1+C2)) (referring to Figure 18 B) generates does not have the DC skew.
Figure 14 has shown the circuit that is used for according to generate tracking error signal 35 from the detection output signal of the photodetector 81 shown in Figure 13 A.Circuit as shown in figure 14 has 88,89 and multipliers 90 of 85,86,87, two totalizers of three subtracters, is used for generating tracking error signal 35 according to above formula (A-D)-K * ((B1+B2)-(C1+C2)).
Figure 15 has shown the circuit that is used for generating according to the combination from the detection output signal of the photodetector 81 shown in Figure 13 B or the 13C tracking error signal 35.Circuit as shown in figure 15 has 93,94,95 and multipliers 96 of three subtracters, is used for generating tracking error signal 35 according to formula (A-D)-K * (B-C).
Can be according to the combination of 81,82 detection output signal being generated focus error signal shown in Figure 1 36 from photodetector.Figure 11 A has shown at object lens 23 when optical axis moves and be displaced to just in time the opposite side of the position that focuses on to 11C, the light beam spot that detects on photodetector 81,82.The light beam spot that detects on photodetector 81,82 is focused with respect to the shape of the position that just in time focuses on basic symmetry.
As shown in figure 12, draw out from the difference between the detection output signal of photodetector 81,82.In the position that just in time focuses on, be zero substantially from the difference between the detection output signal of photodetector 81,82.Therefore, can be based on how much detecting from the difference offset from zero between the detection output signal of photodetector 81,82 from the position deviation of the position that just in time focuses on.This has indicated, can be according to from generating focus error signal 36 along the difference between the detection output signal of the photodetector 81,82 of light path arrangement.
Figure 16 has shown the circuit that is used for generating according to the combination from the detection output signal of the photodetector shown in Figure 13 A 81,82 focus error signal 36.Circuit as shown in figure 16 has 99,100,101,102,103,104 and three subtracters 105,106,107 of six totalizers, is used for according to formula (A+D)-(B1+B2+C1+C2+E)-((F+H)-G) generates focus error signal 36.
Figure 17 has shown the circuit that is used for generating according to the combination from the detection output signal of the photodetector shown in Figure 13 A or the 13B 81,82 focus error signal 36.Circuit as shown in figure 17 has 110,111 and four subtracters 112,113,114,115 of two totalizers, is used for that ((F+H)-G) generates focus error signal 36 according to formula (A+D)-E-.
The photodetector 81,82 that has the separation light detection zone of the shaping shown in Figure 13 A, 13B and 13C by use, can detect the tracking error signal that does not have skew, promptly can calculate (A-D)-K * ((B1+B2)-(C1+C2)) or (A-D)-K * (B-C) so that detect tracking error signal 35, even object lens 23 are moved radially or CD 20 is tilted so that the optical axis of dislocation Returning beam.If center light detection zone B1, B2, C1, C2 or B, the C of photodetector 81 so are shaped so that the zone that the zeroth order light and the first rank light are overlapped each other is not overlapping, can detect tracking error signal 35 by calculating (A-D)+(F-H)-K * ((B1+B2)+(C1+C2)) or (F-H)-K * (B-C) so.
The detection output signal of exterior light detection zone A, D that can be by calculating photodetector 81 and (A+D) and the detection output signal of interior lights detection zone B1, B2, C1, C2 or B, the C of photodetector 81 and (B1+B2+C1+C2) or the detection output signal of exterior light detection zone F, the H of difference (B+C) and photodetector 82 and (F+H) and the difference between the detection output signal D of the interior lights detection zone G of photodetector 82 poor, i.e. (A+D)-(B+C)-((F+H)-G) comes detection of focus error signal 36.
In the embodiment of explanation, the present invention is applied to using the compact disk equipment of CD 20.But principle of the present invention is not limited to use the compact disk equipment of CD, and also can be applicable to magneto-optical disk apparatus.
Although show in detail and described certain preferred embodiment of the present invention, be to be understood that the scope that to make variations and modifications therein and not depart from claims.
Claims (8)
1. compact disk equipment that is used for light beam irradiates is detected by photodetector behind the optical disc surface its Returning beam is characterized in that:
Track space is that the light beam spot of the described light beam that shines for the spacing of the track of described CD is relatively little, at its zeroth order light of core of the orbital direction of described photodetector and the first rank light non-overlapping portions track space on the direction vertical not with described track
Described photodetector has centrosymmetric at least two pairs of marker spaces with respect to this direction in the direction perpendicular to track; First pair of marker space is formed in the zone of accepting the first rank light; The second pair of marker space is not formed on the overlapping part of zeroth order light and the first rank light overlapping and only accept in the zone of zeroth order light; Between the described first pair of marker space perpendicular to the center of the direction of described track; In the central area of the position formation that does not have described second pair of marker space with other regional compartmentalizations
Obtain the DC component of tracking error amount from the difference of the detection output signal of described second pair of marker space, eliminate the output signal of described DC component by the tracking error amount that obtains from difference and carry out tracking Control according to the detection output signal of described first pair of marker space.
2. compact disk equipment according to claim 1, it is characterized in that: described second pair of marker space be formed on orbital direction in the heart with to orbital direction by the state of dislocation, not overlapping and only accept in the zone of zeroth order light with the overlapping part of zeroth order light and the first rank light.
3. compact disk equipment according to claim 2 is characterized in that: described second pair of marker space forms on the both sides of the center of relative orbit direction direction along ng a path.
4. compact disk equipment according to claim 2 is characterized in that: described second pair of marker space forms on a side of the center of relative orbit direction direction along ng a path.
5. compact disk equipment according to claim 1, it is characterized in that: obtain DC component by B-C, and by the computing tracking error signal of (A-D)-K * (B-C), wherein A, D represent the output signal of described first pair of marker space, B, C represent the output signal of described second pair of marker space, and K represents proportionality constant or function.
6. compact disk equipment that is used for light beam irradiates is detected by photodetector behind the optical disc surface its Returning beam is characterized in that:
Track space is that the light beam spot of the described light beam that shines for the spacing of the track of described CD is relatively little, at its zeroth order light of core of the orbital direction of described photodetector and the first rank light non-overlapping portions track space on the direction vertical with described track not;
Light path arrangement first photodetector and second photodetector along described Returning beam;
Described first photodetector has the centrosymmetric at least two pairs of marker spaces with respect to this direction on the direction perpendicular to track, first pair of marker space is formed in the zone of accepting the first rank light, the second pair of marker space is not formed on the overlapping part of zeroth order light and the first rank light overlapping and only accept in the zone of zeroth order light, between described first pair of marker space, on the position that does not have described second pair of marker space, form central area with other regional compartmentalizations perpendicular to the center of the direction of described track;
Described second photodetector has on perpendicular to the direction of track the centrosymmetric a pair of marker space with respect to this direction, has the central area that does not separate at the center simultaneously on the position corresponding with second pair of marker space of described first photodetector and described central area;
Obtain the DC component of tracking error amount from the difference of the detection output signal of second pair of marker space of described first photodetector, eliminate the output signal of described DC component by the tracking error amount that obtains from difference and carry out tracking Control according to the detection output signal of first pair of marker space of described first photodetector; Simultaneously
By the focus servo margin of error that obtains by the difference between the output signal sum of a pair of marker space of the output signal sum of first pair of marker space of described first photodetector and described second photodetector, carry out focus control.
7. compact disk equipment according to claim 6, it is characterized in that: deduct the output signal sum of second pair of marker space of described first photodetector from the output signal sum of first pair of marker space of described first photodetector, and deduct the output signal of the central area of described second photodetector from the output signal sum of a pair of marker space of described second photodetector.
8. compact disk equipment according to claim 6, it is characterized in that: by ((A+D)-(B+C))-((F+H)-G) comes the computing focus error signal, wherein A, D represent the output signal of first pair of marker space of described first photodetector, B, C represent the output signal of described second pair of marker space, F, H represent the output signal of a pair of marker space of described second photodetector, and G represents the output signal of central area.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP238380/04 | 2004-08-18 | ||
| JP238381/04 | 2004-08-18 | ||
| JP2004238380A JP2006059416A (en) | 2004-08-18 | 2004-08-18 | Optical disk device and its control method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1750137A CN1750137A (en) | 2006-03-22 |
| CN100354945C true CN100354945C (en) | 2007-12-12 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNB2005100926928A Expired - Fee Related CN100354945C (en) | 2004-08-18 | 2005-08-18 | Optical disk apparatus and method of controlling optical disk apparatus |
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| Country | Link |
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| JP (1) | JP2006059416A (en) |
| CN (1) | CN100354945C (en) |
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| JPWO2014203528A1 (en) * | 2013-06-21 | 2017-02-23 | パナソニックＩｐマネジメント株式会社 | Optical head device and optical information device |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH01125482A (en) * | 1986-11-14 | 1989-05-17 | Raymond B Bushnell | Air-actuated key |
| US5111449A (en) * | 1988-04-20 | 1992-05-05 | Sharp Kabushiki Kaisha | Optical pick-up device using diffraction grating element having two sub-regions |
| JPH10269588A (en) * | 1997-03-21 | 1998-10-09 | Sharp Corp | Optical pickup device and optical disk recording/ reproducing device |
| JP2000251277A (en) * | 1999-02-24 | 2000-09-14 | Pioneer Electronic Corp | Device and method for detecting focus error of optical pickup |
| JP2001006188A (en) * | 1999-06-23 | 2001-01-12 | Nec Corp | Optical head |
-
2004
- 2004-08-18 JP JP2004238380A patent/JP2006059416A/en active Pending
-
2005
- 2005-08-18 CN CNB2005100926928A patent/CN100354945C/en not_active Expired - Fee Related
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH01125482A (en) * | 1986-11-14 | 1989-05-17 | Raymond B Bushnell | Air-actuated key |
| US5111449A (en) * | 1988-04-20 | 1992-05-05 | Sharp Kabushiki Kaisha | Optical pick-up device using diffraction grating element having two sub-regions |
| JPH10269588A (en) * | 1997-03-21 | 1998-10-09 | Sharp Corp | Optical pickup device and optical disk recording/ reproducing device |
| JP2000251277A (en) * | 1999-02-24 | 2000-09-14 | Pioneer Electronic Corp | Device and method for detecting focus error of optical pickup |
| JP2001006188A (en) * | 1999-06-23 | 2001-01-12 | Nec Corp | Optical head |
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| Publication number | Publication date |
|---|---|
| JP2006059416A (en) | 2006-03-02 |
| CN1750137A (en) | 2006-03-22 |
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